The Strongest Man in the World
by Kishoto
Summary: A poorly utilized Quirk followed by a borderline cliché misunderstanding brings All Might into the One Punch Man world and straight into a fight with the strongest foe he's ever fought.


**A/N: Minor note; this story takes place in a world where All Might beat All for One but managed to avoid taking his career ending injury and so he's at his peak combat potential. Stronger even, thanks to the extra five years on the job!**

* * *

"Keep quiet. If you do, no one has to get hurt."

The man nodded fearfully, staring at the gun barrel held pointed at his head. The scruffy young man holding it wore a black domino mask over his face along with a grey turtleneck pulled up to conceal his mouth.

The young man's name was Mori and this was his first heist as a villain. As far as heists go, robbing an electronics store was the definition of small time, but the $2800 he'd gotten from the old geezer made him not particularly care. He wasn't in this for the infamy; he was in it for the money.

The bell at the front door tinkled, indicating a customer had entered the shop. Mori turned to face the door but before he'd even rotated half way, a gust of wind slammed into him, throwing him off of his feet. He flew backwards, slamming into a display filled with DVD players with a crash of breaking glass and crushed electronics.

Mori groaned, clutching at his head as he tried to sit up but found that he couldn't. He was pinned down by a weight on his chest. He opened his eyes and blinked to clear his vision, the spots in them receding as time passed. He gasped as he recognized just what it was keeping him pinned to the display.

A large yellow boot almost half the size of his torso connected to a muscle clad leg in tight, blue and white spandex.

Mori looked up. And up. And up. Craning his neck to look into the face of the large man keeping him pinned with all of the effort it took to swat a fly. The red, blue and white costume covered the man's entire body, perfectly defining each and every muscle spanning his wide frame. Mori knew that each and every single one of them probably contained enough power to tear down a skyscraper. He'd seen videos of this man doing just that.

The grin on his face stretched from ear to ear, leaving his eyes covered in shadow. His blond hair stuck up in two large spikes that should have looked ridiculous but managed to simply add to his awe inspiring presence.

This was someone Mori never thought he would meet. Especially on the receiving end of things. This was the Symbol of Peace, the world's No. 1 Hero, the Strongest Man in the World.

All Might.

Despite the fact that he was smiling, Mori felt a cold pit form in his stomach as All Might looked over his shoulder at the shopkeeper who was staring at him, several feet away from where he'd knocked Mori. The older man's jaw was hanging open in disbelief.

"Don't worry sir, everything's fine now. Why? Because I am here!"

"T-Thank you, All Might-san!" said the clerk, still blinking up in surprise at the sudden appearance of the hero. All Might nodded at him before turning to face Mori, who was still staring up at the hero with a look of abject terror on his face.

"I suppose it's your unlucky day that my DVD player needed fixing."

All Might held up a brown bag proudly, as if to show off that he too had to deal with things like broken DVD players.

Mori placed his hand on All Might's boot, pushing and heaving against it with all his strength. It was like trying to move a mountain.

"Please, cease and desist young man. I've already notified the authorities and they are on their way."

Mori didn't respond; he simply continued pushing against All Might's boot, trying and utterly failing to move the tree trunk sized limb.

All Might sighed, shaking his head. Despite his powers being more than common knowledge, Quirkless villains still struggled almost every time he apprehended them. It was uncanny; the will to survive and be free that resided in every human, regardless of circumstance or good sense. It was admirable, if somewhat foolish in this case.

"That won't help. Just sit tight and wait for the police to arrive."

Mori gritted his teeth, grunting with effort. Sweat began to run down his forehead and All Might wondered if he was going to injure himself struggling. Perhaps he should let him up and find another way to restrain him.

Before he could do so, All Might felt warmth growing on his foot and he looked down at where the villain's hands were on his boot. They were glowing a sickly green.

" **Kai!** "

The green light discharged, running through All Might's entire body in the time it took him to blink. Before he could even think about stepping backwards, the man known as All Might vanished.

Mori panted, lolling his head back against the display as a sense of deep exhaustion overtook him. He felt faint; fainter than he ever had before. It felt like every last drop of energy in his body had been spent and it took everything he had to simply remain conscious. He barely registered the screaming of the store clerk, focusing the entirety of his attention on staying awake. If he could recover in time, then he could still get away. That was the last thought Mori had before he lost the struggle to stay awake.

The police arrived several minutes later, taking Mori into custody. He was taken to the hospital where the doctors attempted to treat his exhaustion but nothing they tried worked. He was transferred from facility to facility repeatedly, resisting any and all attempts to bring him out of the coma he'd fallen into soon after entering police custody. Even Recover Girl was unable to do anything for him.

After some investigation, his full name, Yamato Mori, was discovered and this allowed them to retrieve the records of his Quirk registration. It was filed under the name "Hide and Seek". Mori was able to make objects disappear and retrieve them at his will. The objects appeared to be completely undamaged by the transition, though hot food would become cold and ice cubes would melt, indicating that time did pass, wherever it was that he sent them. The larger and heavier the object, the more strain it put on Mori's body. Estimates said that vanishing anything over the size of a large cat would be a major threat to Mori's health.

All Might was much larger and much heavier than any cat.

Mori remained in his coma, unresponsive to all forms of stimuli, and the world panicked; trying everything it could think of to retrieve the Symbol of Peace. Hundreds of Quirks tried and failed to so much as locate the missing hero. Nothing worked. Days passed. Mori remained in his coma. And All Might remained gone.

* * *

"I'll cover the west side of the city; you cover the right!" shouted Mumen Rider as he pedaled, his legs pumping his bicycle forward at impressive speeds. Saitama kept up with him, moving at a lax jog. Even still, he had to be careful to not outpace his fellow hero.

"Ok." Said Saitama.

"And remember, these guys are tricky. They're supposed to be pretty strong but the biggest thing is that they're masters of deception! So trust no one!"

"Even you?" asked Saitama mildly.

Mumen Rider laughed, peeling away and down a side street tracking westwards. Saitama turned right, picking up his pace slightly as he moved through, his eyes peeled. He hadn't been jogging for very long before he heard a cry.

"Help! Help me, someone please!"

Saitama slid to a stop, kicking up a small cloud of dust as he looked around for the source of his voice. A woman rounded the corner ahead of him, tripping and almost falling over herself.

"Please, somebody help me!" she shouted, spotting Saitama's yellow suited form. He blinked at the woman's sudden appearance.

"Is everything alright, miss?" he asked politely. He looked around but he didn't see anything out of place and his hearing didn't register anything out of the ordinary.

"Please, Hero-san, help!" shouted the woman, running towards Saitama. Saitama noticed that, despite her earlier clumsiness, the woman's footsteps were becoming faster and surer with every step she took towards him. He was also pretty sure this city was supposed to be deserted with a capital D.

"Ah." He said mildly.

Once she was in reach, the woman's tear stricken face shifted into a manic grin and she swung, her hand crashing into the side of Saitama's head with enough force to send up a huge cloud of dust. She chuckled, her features morphed and twisted into a monstrous visage.

"So gullible. You're just like all the rest of your kind. Eager to please and ever unsuspecting of a pretty…face…"

The monster trailed off as the dust cleared, revealing Saitama's completely unblemished face. He stared dispassionately at the monster mimicking a human woman, his arms folded.

"That's a good costume you've got there." Said Saitama, nodding. "Almost as good as mine."

Saitama cocked back his hand and swung but the monster jumped back, his swing only just missing.

"Too slow." lamented Saitama. This thing was fast, if not all that strong.

As it were, the air pressure created by his stretched out palm alone was enough to split the imposter's blouse in two down the middle, the pieces of fabric now only barely preserving the monster's modesty as they billowed in the sudden gust.

The monster covered herself, her cheeks reddening as her face morphed back into that of a woman's.

"H-H-Hentai!" she screamed, frantically shuffling backwards.

Saitama blinked again, scratching his chin thoughtfully.

"But you're not even a real woman, monster-san." Said Saitama.

The mimic growled but didn't refute his point. She continued to back away only to bump into something. She blinked and turned, now face to face with Saitama's flat expression. She gasped, frantically shuffling backwards as Saitama drew his fist back, sliding his foot backwards with the motion in preparation for a lunge. The woman's face formed into a fearful expression and she closed her eyes, gritting her teeth.

"Hold it right there villain!"

The booming voice came from atop a nearby building. Saitama glanced up, spying a man in a brightly colored, striped suit.

"Villain?" said Saitama, glancing around. He didn't see anyone there besides the three of them but, in looking around, he realized that things must have looked pretty suspicious to an outside observer. He was standing across from what appeared to be a woman with torn up clothing and a terrified expression on her face with his fist raised in the air. Even considering his immensely heroic looking outfit, the scene couldn't have looked worse.

"It's not what it looks like?" said Saitama.

In response, the unknown man jumped, the arc carrying him dozens of meters through the air to land perfectly in between Saitama and the impersonator. The man loomed over Saitama by over a foot and a half and that wasn't including the blonde forelocks that spiked vertically over his head. The brightly colored spandex highlighted a muscular frame that made Saitama, who was average sized by all account, look miniscule in comparison. He had a large grin on his face and his eyes were barely visible, shadowed as they were.

"Fear not, young lady, for I am here!" said the towering giant of a man. "Now, please, run away as fast as you can while I deal with this miscreant."

"Thank you, Hero-san!" she said tearfully, hugging him around his waist. She flashed an ugly smile at Saitama from her position before releasing the unknown man and running away, keeping her pace at a distinctly human level.

Saitama tilted his head at the man, who had yet to take his eyes off of the yellow clad hero.

"That lady's not a lady, man." Said Saitama conversationally.

"Ah, so you're one of those, hmm?" said the blond man. "You judge those that are shaped differently by their Quirks."

"No." said Saitama, wondering what the hell a Quirk was. "I judge those that try to put their fist through my face. Not to sound childish but…"

Saitama raised a finger in the air pointedly.

"She hit me first."

"I know. I saw your fight. But that punch you were about to throw…"

For just a moment, piercing green eyes were visible in the deep shadows of the man's eyes.

"You were going to kill her, weren't you?"

"Yea, probably." Said Saitama, shrugging. It's not as if she hadn't just tried to do the same to him.

"I would expect nothing less from a villain." He said, though his smile didn't waver.

"I'm no villain. I'm a hero." He said.

"I may not be in Japan anymore, the last few unpleasant days I've spent here have made that clear, but it is an accepted, nigh universal truth that heroes don't use lethal force on those too weak to defend themselves. Why? Because I have made it so."

The man widened his stance, his arms curling outwards and his chest thrust forwards. His muscles flexed, straining against the spandex with the motion that served to make the man appear even larger than he already was.

"For I am All Might, the Symbol of Peace! And as long as I stand, villainy and injustice shall not! And that includes those that would falsely claim to be heroes and attempt to take advantage of the weak!"

Saitama rolled his eyes at the display. This guy was probably just another monster sent to catch him off guard and save its companion. But its acting was phenomenal if that was the case.

Saitama cocked his fist back and swung, his fist blurring as it flew towards the larger man.

All Might's left hand moved, quicker than sight, his hand catching Saitama's outstretched fist. The shockwave generated by the swing flew outwards, wind billowing from the point of contact between the two hands. All Might's hair was blown back by the force generated but his grin didn't waver.

Saitama felt a familiar feeling rise up in his chest but he suppressed it. Every time he thought he'd found a challenge, he'd been disappointed. He'd given up on hoping for it.

"Impressive." Said Saitama. "That was a pretty okay punch too."

"Pretty okay. You undersell yourself."

All Might glanced down at where he held the man's smaller fist in his own. The force he'd hit with had been impressive; he could feel his palm stinging sharply. Few that All Might had faced had been able to exert that much power. And this man claimed he wasn't even trying.

"My turn."

All Might drew his right hand back.

" **Detroit** …"

All Might felt the familiar power building in his arm, the energy building and stockpiling throughout his body into the focal point that was his arm.

" **Smash!** "

All Might's hand moved, blurring with the speed with which he brought it down. It hit Saitama directly in the face, the force cratering the ground around them both, sending debris flying. Pieces of concrete and asphalt flew outwards at speeds that would've torn any normal human apart. The dust cloud kicked up by All Might's punch dwarfed the cloud created by Saitama's by a large, definitive margin.

All Might waited for the dust to clear to see what damage he'd managed to inflict. He knew that his opponent was still standing but he couldn't peer through the smoke and identify just how much he'd hurt them. He didn't want to kill them, after all.

The cloud began to clear, thinning as the wind blew, revealing Saitama's unmarred face. His eyes were crossed staring at the fist that was resting flush against his forehead. He raised his arm and placed a finger onto the middle knuckle. With a flick, he sent the large hand flying away, All Might only barely managing to stay on his feet as the force sent him spinning away from Saitama. He righted himself quickly, keeping his eyes firmly on Saitama. He couldn't afford to look away, not even for a second.

"That was a strong hit." Said Saitama appreciatively. No one had hit him that hard since Boros and he got the sense that the punch he'd hit him with wasn't even close to the full force of what he could deliver. Perhaps this could be a good fight after all.

Saitama disappeared from view but All Might was unfazed, pivoting on the spot and swinging his hand to the left. His fist met Saitama's; the man suddenly appearing next to All Might in a burst of speed. All Might stumbled at the impact but managed to keep on his feet, if just barely.

"What…what was that power?" asked All Might, his grin almost faltering in face of the overwhelming force.

"That was my **Slightly Above Average Punch**." Said Saitama. He drew his fist back but All Might moved; the air whistling with his speed as he ducked the swing. He tackled Saitama around the middle, his arms finding purchase on Saitama's smaller body. All Might's immense, muscular frame made grabbing Saitama an easy task and he gripped the man by his waist, hoisting him into the air. He charged with a mighty yell, slamming Saitama into and through the wall of the skyscraper in front of him.

The wall crumbled immediately, as if it was made of tissue paper instead of reinforced concrete, and All Might continued his charge, slamming Saitama through the wall beyond that and the wall beyond that, decimating one entire section of the skyscraper's ground floor in a single charging motion, using Saitama's body as a battering ram the entire way. The building rumbled, leaning precariously as a quarter of its foundation was obliterated by the man called the No. 1 hero.

Once back out into the open air, All Might adjusted his grip and stopped his charge suddenly, using the momentum to pivot his feet once again as he arched backwards, almost forming a bridge with his back as he brought Saitama slamming down into the ground headfirst.

" **Pittsburgh Suplex!** " shouted All Might,

The force embedded Saitama's body into the asphalt with ease, as if he was a nail and All Might a hammer.

All Might released him, jumping several meters back, clear of the man's prone form andwatching for what Saitama would do next. He didn't have to wait long. Saitama kicked his feet, the maneuver almost comical as he flailed about with over half of his body embedded in the ground. His feet began to move faster and faster, becoming invisible to the naked eye with the speed they began to move at. All Might squinted against the dirt that was sent flying by the wind Saitama was incidentally generating.

Saitama's body sank into the ground, disappearing entirely from sight as a noise like a jackhammer resounded across the empty street. All Might held his fists up, never dropping his guard as the noise continued. He knew what was happening; his opponent had dug into the street and was moving beneath him, waiting to strike. He'd fought people with Excavation type Quirks before, though this man appeared to use raw strength alone as opposed to a special ability.

"What are you?" muttered All Might, keeping his stance locked and his guard up. He only had a brief instant to feel the ground below him tremble but that was enough for All Might to hop to the side right before Saitama emerged, fist first from the ground.

Despite missing, the pressure of the air waves knocked All Might back, off balance as he was. He was sent flying end over end, slamming into and through the glass display of a store. The force of his punch had taken Saitama dozens of feet into the air and he looked around thoughtfully, his cape floating in the wind.

"Ah, I missed. Aiming from underground is harder than I thought it would be."

Before Saitama could begin to descend, All Might's form came flying from the store, as if propelled by a spring. He slammed into Saitama, his shoulder leading, and they both flew into the side of a large water tank. Their bodies effortlessly tore through the shaped metal, the tank almost exploding as water flew everywhere in a fine mist.

The two heroes continued their arc, Saitama once again held in All Might's grip. The older hero had taken the opportunity to maneuver Saitama into a sleeper hold. He squeezed down, putting pressure onto the elbow joint framing Saitama's neck but it was as if he was trying to compress diamond. Or something even tougher. He continued squeezing, gritting his teeth as they flew through the air, heedless of where they were going to land but there was absolutely no give. This wasn't going to work.

All Might relaxed his grip on Saitama's neck, kicking off of the man's back and sending him into the ground hundreds of feet below. The force of his kick only propelled him higher and All Might was almost a quarter mile up when he finally stopped, arrested by gravity. He oriented himself downwards as he began to fall, his arms extended. The wind whistled and stung his eyes but they didn't move from his target far below. He could see the other man's yellow costume as clear as day. The man was just looking up at All Might, his arms folded.

All Might continued to fall, gaining more and more speed. He called upon One for All, charging and stockpiling the energy into his extended fists as he fell faster and faster. He began to resemble a brightly colored missile more than anything else as he descended, his streamlined form slicing through the air with a sharp whistling sound.

By the time he'd almost reached Saitama, All Might was moving at speeds approaching Mach 1.

" **Chicago Bomber!** "

Saitama moved suddenly, sidestepping All Might's blow at the very last micro second with an almost casual air. The hero slammed into the earth, his body sinking into the ground in a similar, though much more destructive, way to Saitama's. The strike sent fissures straight through from the point of impact, spreading and spider webbing up and down the street, completely decimating the man made thoroughfare. The crater it formed must have been dozens of feet across and this was more than the tilted skyscraper, already off balance and lacking thirty percent of its foundation, could take.

With a groan of snapping metal and breaking stone, the building fell towards the crater All Might had had, slamming into the new depression and sending up a cloud of dust that covered entire blocks. Saitama stood clear of the fallout, perched on the edge of the roof of an apartment complex that was only just out of range. He put his hand up to his eyes, squinting.

"No way that was enough to take you out." He muttered, standing to his feet. He bent his knees slightly before hopping forwards, the jump sending him arcing directly into the middle of the newly demolished skyscraper. He looked around at the field of glass, metal and brick, wondering where his foe was. He knew he was still here; he could hear his heartbeat. But he couldn't pinpoint his exact location.

With a crash, All Might emerged directly behind Saitama, his arms swinging down to encompass the man's smaller frame yet again, holding Saitama in a full nelson. With the height disparity, Saitama was raised into the air. His feet were left dangling off of the ground, his back held flush against All Might's chest. The captured man rolled his eyes, sighing.

"Again with the wrestling moves? They didn't exactly work before." He commented.

All Might didn't respond; he was panting, his chest heaving as he drew breath. The feedback from the missed Chicago Bomber had been a lot to handle, the force having nowhere to go, and he'd taken all of the backlash as a result. The skyscraper falling on him hadn't exactly helped things either.

"I've taken away your leverage." Said All Might. "Strength ceases to matter if there's no way for you to exert it. Your joints are compromised at these angles; bringing any of that monstrous power to bear would be futile."

Saitama tried to move his arms, finding that it was actually pretty difficult to do. Not impossible, never that, but definitely harder than he would've thought. He kicked his feet experimentally, the limbs swinging in open air, devoid of anything to push off of. Just how tall was this guy?

"You're right. Moving and swinging on you is pretty hard from this angle." Said Saitama.

With almost negligible effort, Saitama flexed his back muscles. From their position against All Might's chest, the muscle moved and bulged, slamming into All Might's torso. All Might gasped, his back bowing as what felt like the force of a thousand shotguns hit him in his chest, almost knocking him to the ground completely. He felt blood at the back of his throat and he could only wonder just how strong you had to be to exert that much force with a simple flexing motion.

Saitama flexed again and All Might gasped again, releasing Saitama andstumbling back from the other man, hacking as he coughed, struggling to breath. That blow had knocked all of the wind out of him and he needed time to recover. A few seconds would do but that could easily be a few seconds too many in a battle like this.

Luckily, Saitama wasn't the ruthless type. He faced away from All Might, allowing him to regain his equilibrium. He rolled his shoulders, stretching them more for effect than anything else.

All Might wiped the blood away from his lip, considering the man before him. This opponent was on an entirely different level from anyone he'd ever faced. He would have to escalate things further; it was the only way to win.

Saying a silent prayer that the city, and any nearby settlements, were completely abandoned, All Might stood tall, folding his arms.

"What's your name?" he asked. He called on One for All, summoning the power in a different way than he usually did. As opposed to calling it up in one quick, explosive burst, he was slowly coaxing it into being, like blowing at the embers of a fire to make it begin to burn. He felt the energy began to coalesce and rise within him.

"The name's Saitama. And you?" he asked, mimicking All Might's pose. He looked much less intimidating.

"I told you; I am All Might." Said the other man. "I admit I am surprised you haven't heard of me."

"Why should I have?" asked Saitama. "I can't keep up with every monster that pops up."

"I am no monster, villain." Said All Might, continuing to summon the power within him. He felt the embers flare into flames and he coaxed them further still. His skin began to take on a luminescent glow; one it hadn't taken on in years, since he'd defeated All for One. It was the sign of One for All building up to unsafe levels within him. "I am the Symbol of Peace. The World's No. 1 Hero."

"Nah, that's Blast." Said Saitama. "If you're gonna lie about yourself, at least be a little more believable. Any kid with a TV could tell you that wasn't true."

"I know not who this Blast is but I get the sense that you are not lying to me; perhaps there's more here than meets the eye. Tell me, Saitama-san. Must our meeting today end in violence? Could we not part ways as friends instead of enemies?"

All Might's question was sincere, though he could guess what the other man's answer would be.

Saitama paused to consider but remembered Mumen Rider's words. These things were masters at deception. Plus there was no way there was a human this strong. He would've heard about him by now. Not to mention he was beginning to glow and spark like some sort of bodybuilder themed Christmas tree which had to be some sort of power up or something. No way was this guy just some human.

Saitama didn't respond verbally; he simply held up his fists and widened his stance. The form was a basic boxing stance, though it was terribly executed.

All Might didn't let the weak guard and opening fool him. He'd seen what his opponent was capable of. He felt One for All beginning to peak and he knew his skin was probably a bright red, crisscrossed with yellow, lightning like veins. He could feel the static building in his hair, the energy sparking between his two forelocks as if they were the terminals of some massive battery. He held his fists out, gritting as his teeth as he encouraged his power to climb further and further, ignoring the limiters that he himself had imposed. If he lost here, it didn't matter whether his body was in one piece. He was done for.

Saitama watched the steam begin to rise off of the other man with interest. What was this guy going to pull off next?

All Might flexed his arms, grunting as he felt the power stop rising, the energy sitting just beneath his skin. He felt almost like an overly filled container, like a balloon ready to pop, but he was used to the feeling. He'd spent years training this form after his fight with All for One. He hadn't encountered anyone strong enough to justify using it against.

Until today, that is.

" **One for All: Stars and Stripes Mode!** "

All Might didn't hesitate; he felt the energy within him begging to be released and he obliged it. One second he was standing several dozen feet across from Saitama; the next he was standing directly over the caped man, his fist swinging down towards him. The very air burned around his hand with the speed and force behind the crushing blow.

" **Detroit...** "

The fist slammed into Saitama's suddenly raised wrist; the force actually moving Saitama back several inches. The bald man's eyes widened as All Might didn't pause, immediately swinging his other fist forward and burying it into Saitama's gut. Saitama took the blow with no ill effect but All Might was undeterred; he brought his other hand around, the fist now visibly on fire from the air friction as it slammed into Saitama's side an instant after the previous hit had landed.

" **Rapid Fire Blitz!** "

All Might continued swinging his arms, his pace unrelenting as he continued to slam them into Saitama's prone body. Each blow did no visible damage but forced Saitama back a precious few inches, his boots sliding straight through the stone with the sheer force. The shockwaves generated by each hit were immense, the ground rumbling as All Might laid punch after punch into Saitama.

Needless to say; the ground around them was all but obliterated by the overwhelming amount of power All Might was bringing to bear. He continued swinging, yelling out with each thrust as he hammered away at Saitama from all sides. The man known as Caped Baldy managed to block maybe two out of every five hits.

"You're faster than me but your guard is full of holes!" shouted All Might, continuing to pound away at Saitama's body, heedless of the damage he was causing to his surroundings. The heat continued to rise around them as the air continued to burn with the speed that All Might was moving at.

Saitama raised an open palm catching All Might's left hand in a sudden grip that stopped it cold. He drew his right fist back but All Might leapt forward, his knee slamming into Saitama's unprotected chin. Saitama wasn't fazed but the surprise did cause him to release All Might's hand and the hero took advantage of the opening, raising both hands and clasping them over his head before bringing them down in a massive, double handed hammer blow directly onto the top of Saitama's head.

Once again, Saitama was forced into the ground, his body sent dozens of feet downwards through the earth as the crater around them widened even further, now well over the size of a city block. He lay on his back, blinking at the sudden darkness around him. He was staring up from the bottom of a shaft beneath the earth, clearly created by his body. The light of day shone down on him from a hole far above.

This new form was fast. Really, really fast. Still not faster than him but much faster than anything that weirdo Sonic-Sonic or whatever could do.

Saitama didn't get much time to ruminate as the light above him was quickly blotted out by a familiar, muscled form. All Might leaped down the newly created shaft, his feet bouncing off of the sides as both gravity and his own power sent him spiraling towards Saitama at speeds far exceeding the speed of sound. It was only at the last possible second that All Might rotated, bringing his elbow to bear and slamming it into Saitama's chest with the sum total of his momentum; the force sending the man even further underground and away from All Might.

Saitama didn't waste any time. He oriented himself quickly, stopping his descent and leaping upwards. He was moving so fast that by the time All Might had heard the sonic boom generated by his movements, Saitama had already tackled the man, sending them both upwards and into the air once more. Saitama grabbed All Might around the waist in a general approximation of what All Might had done to him earlier, flinging him towards the ground. Saitama shifted his body, kicking at the air behind him with a bit of effort.

The kick generated a massive blast of air pressure that sliced upwards, cutting straight through the clouds above them for miles and miles. This also had the intended effect of sending Saitama straight downwards at an angle towards All Might. His fists slammed into All Might's stomach, the force causing All Might to grunt in pain and bend forward, the air knocked out of him once more.

They both hit the ground and were sent rolling. Saitama got to his feet quickly, springing up to stand with his hands held up in his mediocre boxing stance. He patiently gave All Might time to get to his feet. The taller man coughed again, wiping blood from his mouth once more. That hit had done real damage; it would've completely destroyed his internal organs if he hadn't been in Stars and Stripes Mode. As it were, he could feel more than one broken rib in his chest, along with how knew how many micro fractures.

All Might got to his feet, feeling his body throb with both the ache from Saitama's hit and from his time spent in Stars and Stripes Mode. This was not a mode meant for extended fights; it was intended to finish things quickly in an explosive burst of power before leaving All Might to recover. After this mode was turned off, he was completely cut off from his connection to One for All as his reserves recharged over the course of a full day. He temporarily reverted to the Quirkless man he'd been before he'd been gifted this power.

That along with the damage he did to himself with every enhanced swing and step meant that he had to end this.

All Might called upon even more of One for All's power, the flames within himself growing to blazing, inferno-like heights. He felt his muscles begin to expand, the fibers tearing and repairing themselves simultaneously as his human body struggled to contain a power it was not designed to hold. His skin became almost cherry red and his green eyes, normally hidden in shadow, became bright and luminescent, glaring out at Saitama from under his brow.

Throughout the entirety of the battle, All Might's smile had never faded but he let it go this time. His expression fell into one of deep concentration and he gritted his teeth, the hair spikes on his head beginning to waver and spark with excess power. His costume struggled to contain him as he grew, adding several inches to his already impressive height. It didn't help that the spandex was covered in tears and rips from his previous exertions. It was only just barely able to hold him and the material looked ready to give way at any moment.

"Wow, you look even stronger." Said Saitama appreciatively, clapping his hands. This guy had already tanked several of his hits, practically without flinching. He'd been holding back less and less as the battle went on but this guy – All Might – continued to keep up. Or at least not die instantly. He was even tougher than Boros.

But that meant Saitama definitely had to put him down; Boros had almost destroyed the planet. There was no telling what this guy would do if he tried.

"It's time to end this, Saitama!" shouted All Might, the polite honorific forgotten, such was his focus on defeating the bald man.

"I agree. It's getting late. My favorite convenience store is closing soon and I haven't had dinner yet." Said Saitama. "So bring it on; let's see what you got."

"Gladly."

All Might leaped forwards at speeds that made sound seem slow but Saitama was ready this time. He drew his fist back and swung it forwards, consciously pushing himself to exert just a bit more effort than he usually did.

All Might's right arm swung forward, sailing directly towards Saitama's incoming hand. He concentrated every last ounce of One for All into his arm, the towering inferno inside of him compressing itself into a single white hot pillar, focused on the center of his hand. He felt each bone in his hand begin to crumble one after the other but he ignored the pain.

Saitama's eyes narrowed slightly and his expression changed, his fist clenching even tighter as he put just that little extra bit of effort into his swing. He'd need to put in just a bit more than he had with Boros.

All Might roared as his right arm reached forward to impact against Saitama's fist. As the motion began to complete, he released the power completely, focusing it all onto the outlet that was the fist made by his right hand. One for All's full destructive might lanced outwards and down through All Might's arm, the energy releasing itself in one final, explosive burst.

" **One for All: Bursting Global Impact!** "

Saitama exhaled, shaking his head slightly.

" **Serious Punch: Level 1.01.** "

There was no contest.

The force from Saitama's punch tore completely through One for All's power. His fist hit All Might's, shattering the already unstable appendage and knocking All Might's arm off, the limb tearing away from All Might's shoulder in a swift, clean motion. The hero was knocked back, sent flying by the force of the punch. Luckily, due to Saitama shifting his aim slightly, most of the force had missed him and simply flew straight past him.

The brunt of Saitama's punch hit empty air but the sheer force sent that empty air forward like a battering ram. It tore through the city, smashing straight through anything in its way. Buildings and roadways fell before the propelled wall of air, completely vaporized by the sheer scale of the force they were hit with. The force continued, carving out a deep, wide trench of obliteration in the city until it finally dissipated enough that the air stopped disintegrating things and merely toppled them like fragile dominoes.

When all was said and done, anything that had the displeasure of being thirty miles in a vaguely eastward direction from Saitama's punch didn't exist as anything but particulate matter anymore.

All Might's body was sent pin wheeling through the air, the amount of force that had hit him puny in comparison. But it was still enough to knock All Might unconscious instantly while sending him over four miles through the air. His body flopped uselessly, its muscles fading as One for All's power did, burnt out from the overuse. He sailed through clouds and empty sky, arcing up further and further before slowly beginning to descend towards a lake that sat on the outskirts of the decimated city.

He hit the water, sending up a massive column of it and scattering the wildlife surrounding it. His body continued to grow skinnier and skinnier as he sunk further beneath the lake and by the time he came to rest on its bed, All Might was gone and the almost skeletal form of Toshinori Yagi was in his place. Blood leaked from the stump of his right arm, spreading through the water in scarlet clouds.

Bubbles leaked from Yagi's open mouth, becoming fewer and fewer in number as time passed and he showed no signs of movement. Eventually they stopped completely and the hero known as All Might died.

Back in the city, Saitama scratched the back of his head as he stood next to Mumen Rider on the top of one of the few buildings left standing in the city. The hero would've died if Saitama hadn't remembered him at the last moment and managed to find him and whisk him to safety before the full aftereffects of his blow had hit.

Racing out and finding his fellow hero while keeping ahead of the shockwave created by his Serious Punch had actually made Saitama try. A bit anyway.

Mumen Rider stared slack jawed at the scene of devastated city around them. He turned to face Saitama who looked away, almost embarrassed as he scratched the side of his head.

"I…I may have overdid it."

* * *

At that very moment, after several days in his coma, Yamato Mori passed away. And everything he'd sent to the parallel dimensions his Quirk accessed came back simultaneously.

A deflated soccer ball fell into the empty playground of his elementary school.

An old magazine fell out of thin air, startling the occupants of the apartment Mori used to live in.

A veritable mountain of burger wrappers fluttered into existence, sprinkling the counter of the McDonald's outside of his old school.

Several stacks of bills appeared neatly on the countertop of the electronics store that he'd robbed several days earlier.

And soon after, a soaking wet, skinny blonde man in a heavily damaged All Might costume appeared on the floor. He was missing an arm and was unresponsive. He wasn't even breathing.

The shopkeeper fainted at the sight but luckily, the customer he was servicing was a doctor and she called the ambulance before immediately beginning CPR. She cleared his airway and forced the water from his lungs by pumping his diaphragm before beginning mouth to mouth resuscitation.

The other customers watched from a distance, hearts pounding as the injured man lay, unmoving. However, after several harrowing minutes, something changed.

The blonde man's hand twitched and he took a long rattling breath before opening his eyes.

Toshinori Yagi – All Might – had returned. And he was alive.


End file.
